arch/s390/kernel/traps.c

   1 /*
   2  *  S390 version
   3  *    Copyright IBM Corp. 1999, 2000
   4  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   5  *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   6  *
   7  *  Derived from "arch/i386/kernel/traps.c"
   8  *    Copyright (C) 1991, 1992 Linus Torvalds
   9  */
  10
  11 /*
  12  * 'Traps.c' handles hardware traps and faults after we have saved some
  13  * state in 'asm.s'.
  14  */
  15 #include <linux/kprobes.h>
  16 #include <linux/kdebug.h>
  17 #include <linux/module.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include "entry.h"
  22
  23 int show_unhandled_signals = 1;
  24
  25 static inline void __user *get_trap_ip(struct pt_regs *regs)
  26 {
  27 #ifdef CONFIG_64BIT
  28         unsigned long address;
  29
  30         if (regs->int_code & 0x200)
  31                 address = *(unsigned long *)(current->thread.trap_tdb + 24);
  32         else
  33                 address = regs->psw.addr;
  34         return (void __user *)
  35                 ((address - (regs->int_code >> 16)) & PSW_ADDR_INSN);
  36 #else
  37         return (void __user *)
  38                 ((regs->psw.addr - (regs->int_code >> 16)) & PSW_ADDR_INSN);
  39 #endif
  40 }
  41
  42 static inline void report_user_fault(struct pt_regs *regs, int signr)
  43 {
  44         if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
  45                 return;
  46         if (!unhandled_signal(current, signr))
  47                 return;
  48         if (!printk_ratelimit())
  49                 return;
  50         printk("User process fault: interruption code 0x%X ", regs->int_code);
  51         print_vma_addr("in ", regs->psw.addr & PSW_ADDR_INSN);
  52         printk("\n");
  53         show_regs(regs);
  54 }
  55
  56 int is_valid_bugaddr(unsigned long addr)
  57 {
  58         return 1;
  59 }
  60
  61 static void __kprobes do_trap(struct pt_regs *regs,
  62                               int si_signo, int si_code, char *str)
  63 {
  64         siginfo_t info;
  65
  66         if (notify_die(DIE_TRAP, str, regs, 0,
  67                        regs->int_code, si_signo) == NOTIFY_STOP)
  68                 return;
  69
  70         if (user_mode(regs)) {
  71                 info.si_signo = si_signo;
  72                 info.si_errno = 0;
  73                 info.si_code = si_code;
  74                 info.si_addr = get_trap_ip(regs);
  75                 force_sig_info(si_signo, &info, current);
  76                 report_user_fault(regs, si_signo);
  77         } else {
  78                 const struct exception_table_entry *fixup;
  79                 fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
  80                 if (fixup)
  81                         regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE;
  82                 else {
  83                         enum bug_trap_type btt;
  84
  85                         btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs);
  86                         if (btt == BUG_TRAP_TYPE_WARN)
  87                                 return;
  88                         die(regs, str);
  89                 }
  90         }
  91 }
  92
  93 void __kprobes do_per_trap(struct pt_regs *regs)
  94 {
  95         siginfo_t info;
  96
  97         if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
  98                 return;
  99         if (!current->ptrace)
 100                 return;
 101         info.si_signo = SIGTRAP;
 102         info.si_errno = 0;
 103         info.si_code = TRAP_HWBKPT;
 104         info.si_addr =
 105                 (void __force __user *) current->thread.per_event.address;
 106         force_sig_info(SIGTRAP, &info, current);
 107 }
 108
 109 void default_trap_handler(struct pt_regs *regs)
 110 {
 111         if (user_mode(regs)) {
 112                 report_user_fault(regs, SIGSEGV);
 113                 do_exit(SIGSEGV);
 114         } else
 115                 die(regs, "Unknown program exception");
 116 }
 117
 118 #define DO_ERROR_INFO(name, signr, sicode, str) \
 119 void name(struct pt_regs *regs)                 \
 120 {                                               \
 121         do_trap(regs, signr, sicode, str);      \
 122 }
 123
 124 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
 125               "addressing exception")
 126 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
 127               "execute exception")
 128 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
 129               "fixpoint divide exception")
 130 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
 131               "fixpoint overflow exception")
 132 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
 133               "HFP overflow exception")
 134 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
 135               "HFP underflow exception")
 136 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
 137               "HFP significance exception")
 138 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
 139               "HFP divide exception")
 140 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
 141               "HFP square root exception")
 142 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
 143               "operand exception")
 144 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
 145               "privileged operation")
 146 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
 147               "special operation exception")
 148 DO_ERROR_INFO(translation_exception, SIGILL, ILL_ILLOPN,
 149               "translation exception")
 150
 151 #ifdef CONFIG_64BIT
 152 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
 153               "transaction constraint exception")
 154 #endif
 155
 156 static inline void do_fp_trap(struct pt_regs *regs, int fpc)
 157 {
 158         int si_code = 0;
 159         /* FPC[2] is Data Exception Code */
 160         if ((fpc & 0x00000300) == 0) {
 161                 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
 162                 if (fpc & 0x8000) /* invalid fp operation */
 163                         si_code = FPE_FLTINV;
 164                 else if (fpc & 0x4000) /* div by 0 */
 165                         si_code = FPE_FLTDIV;
 166                 else if (fpc & 0x2000) /* overflow */
 167                         si_code = FPE_FLTOVF;
 168                 else if (fpc & 0x1000) /* underflow */
 169                         si_code = FPE_FLTUND;
 170                 else if (fpc & 0x0800) /* inexact */
 171                         si_code = FPE_FLTRES;
 172         }
 173         do_trap(regs, SIGFPE, si_code, "floating point exception");
 174 }
 175
 176 void __kprobes illegal_op(struct pt_regs *regs)
 177 {
 178         siginfo_t info;
 179         __u8 opcode[6];
 180         __u16 __user *location;
 181         int signal = 0;
 182
 183         location = get_trap_ip(regs);
 184
 185         if (user_mode(regs)) {
 186                 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
 187                         return;
 188                 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
 189                         if (current->ptrace) {
 190                                 info.si_signo = SIGTRAP;
 191                                 info.si_errno = 0;
 192                                 info.si_code = TRAP_BRKPT;
 193                                 info.si_addr = location;
 194                                 force_sig_info(SIGTRAP, &info, current);
 195                         } else
 196                                 signal = SIGILL;
 197 #ifdef CONFIG_MATHEMU
 198                 } else if (opcode[0] == 0xb3) {
 199                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 200                                 return;
 201                         signal = math_emu_b3(opcode, regs);
 202                 } else if (opcode[0] == 0xed) {
 203                         if (get_user(*((__u32 *) (opcode+2)),
 204                                      (__u32 __user *)(location+1)))
 205                                 return;
 206                         signal = math_emu_ed(opcode, regs);
 207                 } else if (*((__u16 *) opcode) == 0xb299) {
 208                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 209                                 return;
 210                         signal = math_emu_srnm(opcode, regs);
 211                 } else if (*((__u16 *) opcode) == 0xb29c) {
 212                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 213                                 return;
 214                         signal = math_emu_stfpc(opcode, regs);
 215                 } else if (*((__u16 *) opcode) == 0xb29d) {
 216                         if (get_user(*((__u16 *) (opcode+2)), location+1))
 217                                 return;
 218                         signal = math_emu_lfpc(opcode, regs);
 219 #endif
 220                 } else
 221                         signal = SIGILL;
 222         } else {
 223                 /*
 224                  * If we get an illegal op in kernel mode, send it through the
 225                  * kprobes notifier. If kprobes doesn't pick it up, SIGILL
 226                  */
 227                 if (notify_die(DIE_BPT, "bpt", regs, 0,
 228                                3, SIGTRAP) != NOTIFY_STOP)
 229                         signal = SIGILL;
 230         }
 231
 232 #ifdef CONFIG_MATHEMU
 233         if (signal == SIGFPE)
 234                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 235         else if (signal == SIGSEGV)
 236                 do_trap(regs, signal, SEGV_MAPERR, "user address fault");
 237         else
 238 #endif
 239         if (signal)
 240                 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
 241 }
 242
 243
 244 #ifdef CONFIG_MATHEMU
 245 void specification_exception(struct pt_regs *regs)
 246 {
 247         __u8 opcode[6];
 248         __u16 __user *location = NULL;
 249         int signal = 0;
 250
 251         location = (__u16 __user *) get_trap_ip(regs);
 252
 253         if (user_mode(regs)) {
 254                 get_user(*((__u16 *) opcode), location);
 255                 switch (opcode[0]) {
 256                 case 0x28: /* LDR Rx,Ry   */
 257                         signal = math_emu_ldr(opcode);
 258                         break;
 259                 case 0x38: /* LER Rx,Ry   */
 260                         signal = math_emu_ler(opcode);
 261                         break;
 262                 case 0x60: /* STD R,D(X,B) */
 263                         get_user(*((__u16 *) (opcode+2)), location+1);
 264                         signal = math_emu_std(opcode, regs);
 265                         break;
 266                 case 0x68: /* LD R,D(X,B) */
 267                         get_user(*((__u16 *) (opcode+2)), location+1);
 268                         signal = math_emu_ld(opcode, regs);
 269                         break;
 270                 case 0x70: /* STE R,D(X,B) */
 271                         get_user(*((__u16 *) (opcode+2)), location+1);
 272                         signal = math_emu_ste(opcode, regs);
 273                         break;
 274                 case 0x78: /* LE R,D(X,B) */
 275                         get_user(*((__u16 *) (opcode+2)), location+1);
 276                         signal = math_emu_le(opcode, regs);
 277                         break;
 278                 default:
 279                         signal = SIGILL;
 280                         break;
 281                 }
 282         } else
 283                 signal = SIGILL;
 284
 285         if (signal == SIGFPE)
 286                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 287         else if (signal)
 288                 do_trap(regs, signal, ILL_ILLOPN, "specification exception");
 289 }
 290 #else
 291 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
 292               "specification exception");
 293 #endif
 294
 295 void data_exception(struct pt_regs *regs)
 296 {
 297         __u16 __user *location;
 298         int signal = 0;
 299
 300         location = get_trap_ip(regs);
 301
 302         if (MACHINE_HAS_IEEE)
 303                 asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
 304
 305 #ifdef CONFIG_MATHEMU
 306         else if (user_mode(regs)) {
 307                 __u8 opcode[6];
 308                 get_user(*((__u16 *) opcode), location);
 309                 switch (opcode[0]) {
 310                 case 0x28: /* LDR Rx,Ry   */
 311                         signal = math_emu_ldr(opcode);
 312                         break;
 313                 case 0x38: /* LER Rx,Ry   */
 314                         signal = math_emu_ler(opcode);
 315                         break;
 316                 case 0x60: /* STD R,D(X,B) */
 317                         get_user(*((__u16 *) (opcode+2)), location+1);
 318                         signal = math_emu_std(opcode, regs);
 319                         break;
 320                 case 0x68: /* LD R,D(X,B) */
 321                         get_user(*((__u16 *) (opcode+2)), location+1);
 322                         signal = math_emu_ld(opcode, regs);
 323                         break;
 324                 case 0x70: /* STE R,D(X,B) */
 325                         get_user(*((__u16 *) (opcode+2)), location+1);
 326                         signal = math_emu_ste(opcode, regs);
 327                         break;
 328                 case 0x78: /* LE R,D(X,B) */
 329                         get_user(*((__u16 *) (opcode+2)), location+1);
 330                         signal = math_emu_le(opcode, regs);
 331                         break;
 332                 case 0xb3:
 333                         get_user(*((__u16 *) (opcode+2)), location+1);
 334                         signal = math_emu_b3(opcode, regs);
 335                         break;
 336                 case 0xed:
 337                         get_user(*((__u32 *) (opcode+2)),
 338                                  (__u32 __user *)(location+1));
 339                         signal = math_emu_ed(opcode, regs);
 340                         break;
 341                 case 0xb2:
 342                         if (opcode[1] == 0x99) {
 343                                 get_user(*((__u16 *) (opcode+2)), location+1);
 344                                 signal = math_emu_srnm(opcode, regs);
 345                         } else if (opcode[1] == 0x9c) {
 346                                 get_user(*((__u16 *) (opcode+2)), location+1);
 347                                 signal = math_emu_stfpc(opcode, regs);
 348                         } else if (opcode[1] == 0x9d) {
 349                                 get_user(*((__u16 *) (opcode+2)), location+1);
 350                                 signal = math_emu_lfpc(opcode, regs);
 351                         } else
 352                                 signal = SIGILL;
 353                         break;
 354                 default:
 355                         signal = SIGILL;
 356                         break;
 357                 }
 358         }
 359 #endif
 360         if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
 361                 signal = SIGFPE;
 362         else
 363                 signal = SIGILL;
 364         if (signal == SIGFPE)
 365                 do_fp_trap(regs, current->thread.fp_regs.fpc);
 366         else if (signal)
 367                 do_trap(regs, signal, ILL_ILLOPN, "data exception");
 368 }
 369
 370 void space_switch_exception(struct pt_regs *regs)
 371 {
 372         /* Set user psw back to home space mode. */
 373         if (user_mode(regs))
 374                 regs->psw.mask |= PSW_ASC_HOME;
 375         /* Send SIGILL. */
 376         do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
 377 }
 378
 379 void __kprobes kernel_stack_overflow(struct pt_regs * regs)
 380 {
 381         bust_spinlocks(1);
 382         printk("Kernel stack overflow.\n");
 383         show_regs(regs);
 384         bust_spinlocks(0);
 385         panic("Corrupt kernel stack, can't continue.");
 386 }
 387
 388 void __init trap_init(void)
 389 {
 390         local_mcck_enable();
 391 }